class Calculadora 
{ 
	private static Calculadora calculadora; 

	public static synchronized Calculadora getInstance() { 
		if (calculadora == null){ 
			calculadora = new Calculadora(); 
		} 
		return calculadora; 
	} 

	private Calculadora(){ 

	}	 
	public int suma (int a, int b){ 
		return a+b; 
	} 

	public int resta (int a, int b){ 
		return a-b; 
	} 

	public int multiplicacion (int a, int b){ 
		return a*b; 
	} 

	public double division (int a, int b){ 
		return a/b; 
	} 

}
public class calcu {
		public static void main(String[] args) {
    	Calculadora calculator = Calculadora.getInstance();
        int s = calculator.suma(5, 6);
        int r = calculator.resta(5, 6);
        int m = calculator.multiplicacion(5, 6);
        int d = (int) calculator.division(9,2);
        System.out.println("5+6=" + s);
        System.out.println("5-6=" + r);
        System.out.println("5x6=" + m);
        System.out.println("9/2=" + d);
    }
}
